Self locking coupling device

0001This invention relates to a coupling device that locks to a coupling member or member to be hooked to prevent inadvertent separation of the two and more particularly to a self locking coupling device that can receive and lock the coupling member in the mouth of a hook without manual actuation of its locking components.

BACKGROUND OF THE INVENTION

0002Removable coupling devices such as hooks are commonly used to temporarily connect two separate objects. Often, it is necessary or desirable to provide a removable connection that can be locked in order to ensure that the two objects are not inadvertently separated before it is desirable to do so. For example, three-point hitch systems for tractors and other agricultural vehicles often feature an upper link having a hook that operates in a locking fashion to prevent detachment of an implement from the vehicle during its use. While described in this context, the present invention is not intended to be limited to this particular application.

0003Upper hooks for three-point tractor hitch systems that lock a coupling sphere or pin of an implement within the mouth of the hook are currently available to prevent accidental separation of the tractor and implement during use. U.S. Pat. No. 4,241,935 and European Patent Application Publication No. 1,403,101 both describe such upper hooks having a latch for controlling the motion of a locking bolt passing through an opening in the hook body for selectively blocking a portion of the hook mouth housing a coupling sphere within. The inventions in the above patent documents each provide a coupling eye on the control lever for attachment of a cable by means of which the control lever can be actuated between latching and unlatching positions from a distance. While this feature allows connection of the upper hook to the coupling sphere without the user having to dismount the tractor seat, actuation of the locking components by the user is still required.

0004U.S. Pat. No. 6,478,094 describes another three-point tractor hitch which allows the attachment of an implement without requiring the operator to leave the tractor seat. The upper link of the hitch includes a stationary jaw having a movable jaw pivotally attached to it in such a way that lowering the movable jaw onto a coupling pin of the implement will cause the movable jaw to pivot upward into the stationary jaw. In this position, the coupling pin is held within the two jaws and a latching mechanism prevents further relative motion of the jaws, thereby locking the pin in place. The length of the upper link is adjustable from the tractor seat as the jaws are connected to the tractor by a linear hydraulic actuator. This invention does not require a control lever to be held in an unlatched position during connection of the hitch and implement. However, the invention requires accurate placement of the upper link such that the movable jaw is positioned directly over the coupling pin, which despite the addition of the hydraulic actuator that can be operated from the tractor seat, can still be difficult and time consuming for a single user.

SUMMARY OF THE INVENTION

0005It is an object of the present invention to provide a coupling device that can connect to a coupling member in a locking fashion without requiring manual actuation of its locking components and overly accurate positioning during the connection process. Such a device would facilitate quick and easy coupling by a single operator.

0006According to a first aspect of the invention there is provided a coupling device comprising:

0007a hook body shaped to define an outer surface with a mouth extending inward from the outer surface of said hook body, said mouth having an end portion spaced from said outer surface, such that a member to be hooked can enter the mouth from the outer surface and move to the end portion to effect coupling between the hook body and the member;

0008a securing member supported on the hook body and extending toward the mouth, said securing member being movable between an extended position in which said securing member substantially obstructs passage of the hooked member to and from the end portion and a retracted position in which said securing member does not substantially obstruct said passage;

0009the securing member being biased toward the extended position;

0010a releasable locking arrangement for locking the securing member in the extended position to prevent unwanted movement toward the retracted position;

0011a releasing member supported on the hook body and presenting an end portion at the outer surface operable by engagement with an element at the outer surface of the hook body to unlock the securing member and allow movement thereof toward the retracted position, actuation of said releasing member thereby opening the passage of the member to be hooked to the end portion of the mouth.

0012The present invention provides a coupling device that can engage a coupling portion of an object in a locking fashion without requiring manual actuation of components or an excessive amount of accuracy in positioning the device for coupling. Contact between a coupling member of the object being connected to the device and the releasing member unlocks the securing member so that it can be pushed by the coupling member to the retracted position in which the mouth of the hook is open. The coupling member moves into the mouth past the retracted securing member to an inner end of the mouth. The securing member is biased toward the extended position so that once cleared by the coupling member, it will return to its locked state in the extending position to secure the coupling member in the mouth.

0013Preferably the hook body has a rectilinear hole extending therethrough to the mouth of said hook body and the securing member is a locking bolt coaxially received in said hole for movement therealong.

0014Preferably there is provided a control lever pivotally coupled to the locking bolt at a pivot point adjacent an end of said locking bolt opposite the mouth, said control lever being movable between a latching position in which the locking bolt is in the extended position and an unlatching position in which said locking bolt is in the retracted position.

0015Preferably the control lever has an abutting surface and the hook body has a bearing surface, the surfaces being spaced from the pivot point to a first side thereof and being arranged to engage upon movement of said control lever from the latching position induced by movement of the locking bolt from the extended position to block further motion of said control lever and said locking bolt, thereby locking said locking bolt in the extended position.

0016Preferably the release member comprises a pin having a first end adjacent the outer surface of the hook body from which the mouth extends and a second end for engagement with the control lever on the first side of the pivot point, said pin being operable with the locking bolt in the extended position by pushing on said first end such that said second end pivots the control lever out of the latching position, thereby disengaging the abutting and bearing surfaces to unlock said locking bolt from the extended position. Preferably the locking bolt is hollow and the pin is received in said locking bolt for movement therealong.

0017Preferably the pin comprises an extension portion extending outward from the locking bolt adjacent the end of said locking bolt opposite the mouth, the second end of said pin being disposed on said extension portion.

0018Preferably there is provided a spring for biasing the securing member toward the extended position such that said securing member tends to return to said extended position after actuation of the releasing member.

0019Preferably there is provided a torsion spring pivotally connected at opposite ends thereof to the control lever and the hook body to bias said control lever toward the latching position such that said securing member tends to return to said extended position after actuation of the releasing member.

0020Preferably the hook body further comprises a groove for receiving an end of the control lever as said control lever reaches the unlatching position, said end being on a second side of the pivot point opposite the first side thereof.

0021Preferably the torsion spring is connected to the hook body on a first side of the pivot point, said torsion spring is connected to the control lever on said first side with said lever out of the unlatching position and said pivot spring is connected to said control lever on a second side opposite said first side with said control lever in the unlatching position such that said control lever is held in the unlatching position with the end of said control lever received in the groove and said control lever is biased toward the latching position when said end is removed from said groove, the securing member thereby tending to return to said extended position after actuation of the releasing member unless said control lever is in the unlatching position.

0022Preferably the mouth extends inward from the outer surface of the hook body at an oblique angle to a longitudinal axis of the hook body.

0023Preferably the control lever comprises a U-shaped channel member having side walls, the locking bolt being disposed between said side walls.

0024Preferably the control lever comprises a recess defining the abutment surface thereof and the hook body comprises a protrusion defining the bearing surface thereof.

0025The hook body may comprise a shaped ledge extending from the first side of the pivot point to the second side thereof, said ledge defining the bearing surface and the groove at opposite ends thereof.

0026There may be provided a support member, the hook body being supported on an end of said support member. In this case, preferably the outer surface of the hook body slopes from the support member toward the mouth of the hook body and the support member comprises a hydraulic cylinder which is adjustable in length.

0027There may be provided a locking pin and the control lever and the hook body may each have a transverse hole therethrough, said holes being aligned with said control lever in the latching position such that said locking pin can be passed therethrough to secure the locking bolt and said control lever in the extended and latching positions respectively regardless of actuation of the release member.

BRIEF DESCRIPTION OF THE DRAWINGS

0028In the accompanying drawings, which illustrate an exemplary embodiment of the present invention:

0029<figref idref="DRAWINGS">FIG. 1</figref> is an isometric view of a coupling device having a coupling pin received in the mouth of a hook body and a control lever raised to an unlatching position in which the mouth is unobstructed by a locking bolt.

0030<figref idref="DRAWINGS">FIG. 2</figref> is a partial side view of the coupling device of <figref idref="DRAWINGS">FIG. 1</figref> having the control lever in a lowered latching position in which the locking bolt obstructs the mouth to secure the coupling pin therein.

0031<figref idref="DRAWINGS">FIG. 3</figref> is a partial side view of the coupling device of <figref idref="DRAWINGS">FIG. 2</figref> before the coupling pin is received in the mouth of the hook body.

0032<figref idref="DRAWINGS">FIG. 4</figref> is a partial side view of the coupling device of <figref idref="DRAWINGS">FIG. 3</figref> after the coupling pin has entered the mouth and caused an operable pin to rise and move the control lever out of the lowered latching position.

0033<figref idref="DRAWINGS">FIG. 5</figref> is a partial side view of the coupling device of <figref idref="DRAWINGS">FIG. 4</figref> after the coupling pin has moved further into the mouth and caused the locking bolt to rise and fully open the mouth.

0034<figref idref="DRAWINGS">FIG. 6</figref> is a partial side view of the coupling device of <figref idref="DRAWINGS">FIG. 1</figref>.

DETAILED DESCRIPTION

0035As shown in <figref idref="DRAWINGS">FIG. 1</figref>, the coupling device <b>10</b> of the present invention is arranged to connect a vehicle, such as a tractor or combine, on which it is mounted to an implement having a coupling pin <b>12</b>. The device <b>10</b> features a hydraulic cylinder having a body <b>14</b> and a rod <b>16</b> which extends away from the vehicle. A hook body <b>20</b> is mounted at an end of the rod <b>16</b> opposite the cylinder body <b>14</b>. At the top of the hook body <b>20</b> is a control lever <b>22</b> that is attached to the hook body <b>20</b> by a torsion spring <b>24</b>. The control lever <b>22</b> is connected to a locking bolt <b>26</b> at a pivot point <b>28</b> and is used to control the position of the locking bolt <b>26</b> that extends vertically downward through the hook body into a mouth <b>30</b> of the hook body <b>20</b> where the coupling pin <b>12</b> is received. The position of the locking bolt <b>26</b> determines whether or not the coupling pin <b>12</b> is locked within the mouth <b>30</b>.

0036<figref idref="DRAWINGS">FIG. 2</figref> shows the device <b>10</b> with the coupling pin <b>12</b> received in the mouth <b>30</b>, the locking bolt <b>26</b> in a lowered locking position and the control lever <b>22</b> in a corresponding lowered latching position. The cylindrical locking bolt <b>26</b> is received in a vertical cylindrical hole <b>32</b> extending down through the top of the hook body <b>20</b> to the mouth <b>30</b>. The control lever <b>22</b> and the locking bolt <b>26</b> are connected by the pivot <b>28</b> near an upper end <b>38</b> of the locking bolt <b>26</b> above the hook body <b>20</b>. A lower end <b>36</b> of the locking bolt <b>26</b> extends into the mouth <b>30</b> when the locking bolt <b>26</b> is in the lowered locking position. It should be appreciated that lifting of the lever <b>22</b> will cause the locking bolt <b>26</b> to rise. The spring <b>24</b> is pivotally attached to the control lever <b>22</b> and the hook body <b>20</b> at its opposite ends <b>40</b> and <b>42</b>. The spring <b>24</b> is designed to pull the lever end <b>40</b> toward the hook end <b>42</b>. With the control lever <b>22</b> in the lowered latching position of <figref idref="DRAWINGS">FIG. 2</figref>, the connection point at the lever end <b>40</b> is on the same side of the pivot <b>28</b> of the lever <b>22</b> as the hook end <b>42</b> thereby biasing the control lever <b>22</b> toward the lowered latching position.

0037With the coupling pin <b>12</b> received in the mouth <b>30</b>, relative rotation of the hook body <b>20</b> and coupling pin <b>12</b> may cause friction tending to move the locking bolt <b>26</b> upward. This motion must be prevented in order to avoid unwanted decoupling of the device <b>10</b> and the implement having the coupling pin <b>12</b>. An abutting surface <b>48</b> is defined by a recess <b>49</b> in the control lever <b>22</b>. A corresponding bearing surface <b>50</b> extends outward from the hook body <b>20</b> just above the abutting surface <b>48</b> with the control lever in the lowered latching position of <figref idref="DRAWINGS">FIG. 2</figref>. It should be appreciated from the figure that upward movement of the locking bolt <b>26</b> from the locking position shown will cause a combination of linear and rotational motion of the control lever <b>22</b>, causing the abutting surface <b>48</b> to move upward against the bearing surface <b>50</b>. The engagement of these surfaces prevents further upward motion of the lever <b>22</b> and the connected locking bolt <b>26</b>. Thus the coupling pin <b>12</b> is secured within the mouth <b>30</b> by the lower end <b>36</b> of the bolt <b>26</b>.

0038The locking bolt <b>26</b> is hollow such that an operable pin <b>64</b> can be coaxially received therein for longitudinal motion relative to the bolt <b>26</b>. As seen in the figures, the operable pin <b>64</b> is somewhat J-shaped. It extends vertically upward through the bolt <b>26</b> from a lower end <b>62</b> to an extension portion <b>64</b> that extends outward from an opening in the bolt <b>26</b> near the pivot <b>28</b> to an upper wall <b>66</b> of the lever <b>22</b> on the same side of the pivot <b>28</b> as the spring <b>24</b> and the blocking surfaces <b>48</b> and <b>50</b>. In a lowered extending position, a bottom end <b>62</b> of the operable pin <b>60</b> extends significantly downward from the lower end <b>36</b> of the locking bolt. It is this operable pin <b>60</b> that allows coupling of the device <b>10</b> and the coupling pin <b>12</b> of the implement without having to manually rotate an end <b>44</b> of the lever <b>22</b> nearest the cylinder body <b>14</b> about the pivot <b>28</b> out of the lowered latching position and lift the locking bolt <b>26</b> out of the locking position in the mouth <b>30</b>.

0039The device <b>10</b> is positioned on the coupling pin <b>12</b> such that the pin <b>12</b> is anywhere between the opening of the mouth <b>30</b> and the cylinder body <b>14</b>. Pulling the hook body <b>20</b> away from the implement having the coupling pin <b>12</b>, for example by compressing the hydraulic cylinder to move the rod <b>16</b> further into the housing <b>14</b>, causes the stationary coupling pin <b>12</b> and the mouth <b>30</b> to get closer together.

0040The bottom surface <b>68</b> of the hook body <b>20</b> is sloped downward from the cylinder rod <b>16</b> to the opening of the mouth <b>30</b> to allow the device <b>10</b> to pass smoothly over the coupling pin <b>12</b> during the relative motion therebetween. When the coupling pin <b>12</b> reaches the mouth <b>30</b>, the weight of the device <b>10</b> causes the hook body <b>20</b> to sink down such that the coupling pin <b>12</b> enters the mouth <b>30</b>. Contact between the coupling pin <b>12</b> and the bottom end <b>62</b> of the operable pin <b>60</b> causes the operable pin to move up relative to the locking bolt <b>26</b> to a retracted position shown in <figref idref="DRAWINGS">FIG. 4</figref>. The operable pin has its lower engagement end contained within a line between the bottom end of the sloped surface <b>68</b> and the tip of the hook so that it is effectively contained within the mouth and is protected by the hook body from being inadvertently engaged.

0041In this position, the extension portion <b>64</b> of the operable pin <b>60</b> pushes up against the upper wall <b>66</b> of the control lever <b>22</b> causing the end <b>44</b> of the lever <b>22</b> to pivot upward about the pivot point <b>28</b> and disengage the abutment and bearing surfaces <b>48</b> and <b>50</b>.

0042With these control surfaces no longer blocking upward movement of the lever <b>22</b> and the locking bolt <b>26</b>, contact with the coupling pin <b>12</b> causes the bolt <b>26</b> to move upward to the unlocking position shown in <figref idref="DRAWINGS">FIG. 5</figref>. In this position, the lower end <b>36</b> of the locking bolt <b>26</b> no longer blocks access to the concave end <b>78</b> of the mouth <b>30</b>, so the coupling pin continues further into the mouth up the straight side wall <b>76</b> until it is nested at the concave end <b>78</b>. With the coupling pin <b>12</b> received in the end <b>78</b> of the mouth, the rectilinear opening <b>32</b> is no longer obstructed by the pin <b>12</b>, and so the spring <b>24</b> snaps the control lever <b>22</b> back to the latching position of <figref idref="DRAWINGS">FIG. 2</figref>. This action of the control lever <b>22</b> causes the attached locking bolt <b>26</b> and the contacting operable pin <b>60</b> to return to their locking and extending positions respectively, as also shown in <figref idref="DRAWINGS">FIG. 2</figref>. With the abutment and bearing surfaces <b>48</b> and <b>50</b> of the control lever <b>22</b> and hook body <b>20</b> once again engaged, the coupling pin <b>12</b> is secured within the mouth <b>30</b> of the device <b>10</b>. In addition to the control surfaces <b>48</b> and <b>50</b>, movement of the lever <b>22</b> and locking bolt <b>26</b> relative to the body <b>20</b> can be further prevented by passing a locking pin <b>45</b> through the aligned holes <b>46</b> in the hook body <b>20</b> and control lever <b>22</b>.

0043To disengage the coupling pin <b>12</b> from the device <b>10</b>, the control lever <b>22</b> is manually pivoted about the pivot point <b>28</b> to disengage the abutment surface <b>48</b> of the lever <b>22</b> and the bearing surface <b>50</b> of the hook body <b>20</b>. The end <b>44</b> of the lever <b>22</b> is then lifted to move the lever <b>22</b> into the unlatching position shown in <figref idref="DRAWINGS">FIG. 6</figref>. Here, another end <b>80</b> of the lever <b>22</b> on a second side of the pivot point <b>28</b> opposite the first side is received in a groove <b>82</b> provided near the top of the hook body <b>20</b>. The groove <b>82</b> is defined within a ledge <b>84</b> that protrudes outward from the hook body <b>20</b> along the top thereof. The control lever <b>22</b> is held in this position by the spring <b>24</b> and groove <b>82</b>, as it can be seen in the figure that the lever end <b>40</b> of the spring <b>24</b> is located on the second side of the pivot point <b>28</b> in this position. As a result, the ends <b>40</b> and <b>42</b> of the spring <b>24</b> pulling toward one another does not cause the lever <b>22</b> to pivot back toward the latching position of <figref idref="DRAWINGS">FIG. 2</figref> until the end <b>80</b> is manually removed from the groove <b>82</b>. The end of the ledge <b>84</b> opposite the groove <b>82</b> defines the bearing surface <b>50</b> of the hook body <b>20</b>.

0044In the unlatching position of <figref idref="DRAWINGS">FIG. 6</figref>, the pivot point <b>28</b> at which the control lever <b>22</b> and the locking bolt <b>26</b> are connected is high enough to withdraw the lower end <b>36</b> of the locking bolt <b>26</b> and the bottom end <b>62</b> of the operable pin <b>60</b> from the mouth <b>30</b> through the rectilinear opening <b>32</b>. With the mouth <b>30</b> unobstructed, pushing the hook body <b>20</b> against the coupling pin <b>12</b> will cause the device <b>10</b> to rise up off the pin due to engagement of the pin <b>12</b> and sloped side <b>84</b> of the mouth <b>30</b>, eventually returning the pin <b>12</b> to the bottom surface <b>68</b> of the hook body.

0045As seen in <figref idref="DRAWINGS">FIG. 5</figref>, the hook body <b>20</b> features a stationary obstruction pin <b>70</b> that extends partially into the rectilinear opening <b>32</b> and serves to limit motion of the locking bolt <b>26</b> with respect the hook body <b>20</b>. A longitudinal groove <b>72</b> is provided in a side of the locking bolt <b>26</b> for engagement with the obstruction pin <b>70</b>. A lower end <b>74</b> of the groove <b>72</b> engages the pin <b>70</b> to prevent upward motion of the locking bolt <b>26</b> passed the unlocking position in which the mouth <b>30</b> is not blocked by its lower end <b>36</b>. This corresponds to the unlatching position of the control lever <b>22</b> shown in <figref idref="DRAWINGS">FIG. 6</figref>. Similarly, an upper end <b>76</b> of the longitudinal groove <b>72</b> engages the pin <b>70</b> to prevent downward motion of the locking bolt <b>26</b> passed the locking position in which the mouth <b>30</b> is blocked by its lower end, corresponding to the latching position of the control lever <b>22</b> as shown in <figref idref="DRAWINGS">FIGS. 2 and 3</figref>. The groove <b>72</b> and obstruction pin prevent the locking bolt from being pulled up entirely out of the rectilinear opening <b>32</b> by the lever <b>22</b>.

0046It should be appreciated from <figref idref="DRAWINGS">FIG. 1</figref> that the control lever <b>22</b> is a U-shaped channel member defined by side walls <b>88</b> connected by a curved upper wall <b>86</b>. As a result, the spring <b>24</b> is disposed between the side walls <b>88</b> along with the extension portion <b>64</b> of the operable pin <b>60</b> and the upper end <b>38</b> of the locking bolt <b>26</b>. The hook body <b>20</b> and the control lever <b>22</b> are each generally symmetric about a vertical plane extending along a central longitudinal axis of the device <b>10</b> such that the above description referring to the side views of <figref idref="DRAWINGS">FIGS. 2-6</figref> applies to each side of the coupling device.

0047The hydraulic cylinder is used to provide the coupling device <b>10</b> with an adjustable length. The cylinder rod <b>16</b> can be extended from and retracted into the cylinder body <b>14</b> as needed to adjust the length of the device. This feature can be used to pull the hook body <b>20</b> over the coupling pin <b>12</b> for attachment and to push the hook body against the pin <b>12</b> to remove it from the mouth <b>30</b>. When used as an upper link for a three-point hitch, the device can therefore be adjusted by hydraulic controls provided on the tractor. The present invention can be used to quickly and easily couple an implement and a tractor together, as the control lever need not be manually actuated to facilitate a locking connection. Furthermore, accurate positioning of the mouth <b>30</b> is not required to connect the device <b>10</b> and the coupling pin <b>12</b>, as coupling can be achieved by merely pulling the hook body <b>20</b> over the pin.

0048While described for use in the secure connection of agricultural implements and vehicles, it should be appreciated that the coupling device of the present invention is not limited to that particular use. Furthermore, while the detailed embodiment features a locking bolt <b>26</b>, operable pin <b>26</b> and control lever <b>22</b>, arrangements featuring alternate securing members and release members may be used to achieve a similar result. The concept behind the present invention is to provide coupling device wherein the securing member that prevents detachment of the connected implements is locked in place by default unless a releasing member is actuated by contact with the coupling element to open the mouth of the hook. This results in the elimination of both the need for manual actuation of locking components and overly accurate positioning of the device to achieve secure coupling. In the detailed embodiment, the mouth <b>30</b> extended upward from the bottom outer surface <b>68</b> of the hook body <b>20</b> and the locking bolt <b>26</b> and operable pin <b>60</b> extended vertically. This arrangement allows coupling to be achieved by the weight of the device <b>10</b> being exerted on the coupling pin <b>12</b> through the operable pin <b>60</b>. It should be appreciated that the device <b>10</b> may be used in other orientations wherein the force between the coupling and operable pins <b>12</b> and <b>60</b> required for opening the mouth <b>30</b> is not provided by gravity.

0049Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.